Of course, it is almost impossible to save any money making your own clothes, now that so many clothes are made by low-paid workers in Asia. However, altering and mending is much more economical. I can fix rips and torn seams, and reattach buttons and other fasteners. I've done this for about ten garments in total from every member of my family in the last year.
Beyond repairing buttons, the next sewing level is to be able to alter clothes. I like to buy consignment clothes, and have bought a number of blazers for $10 at Goodwill which look great---if they fit correctly. I weigh about 235 pounds and am only 5'10", so my torso is quite thick compared to the length of my arms. Also, I have a separated left shoulder, which makes my left arm about 3/4" longer than my right. I can sometimes find clothes which were altered by the previously owner so they fit well---but that of course limits my options to about 1/5th of the clothes that fit me in the chest and shoulders (which is they basic, unalterable sizing for men's coats and shirts.)
So I bought a blue plaid blazer at Goodwill, while I was buying some clothes for my son, as an experiment in alteration. It fits me in the shoulders. It is too tight in the tummy---possibly it is is a trim cut. I didn't even think to button it in the store, but the point is to experiment in any case. But the sleeves were 2" too long. I studied a 45 minute video by a professional tailor on how to shorten the sleeves on a man's jacket---but I STILL don't understand how to do it so that you can machine stitch the lining back into the sleeves. It has something to do with making a hole in the lining so you can turn it inside out---but apparently I am too stupid to understand it. Finally I gave up and found an article that just said to whip-stitch the lining in place by hand, which worked well.
Like all but the most expensive men's jackets, the buttons on the sleeves are not functional. They are just decoration left over from the day when men wore coats as a matter of course, and might have to actually "roll up their sleeves". In the case of this jacket, the 2" taken off actually removed the entire "vent" on the sleeve. If you shorten a jacket sleeve, you always have to move the buttons---but that is one of the easy things I know how to do.
In fact, I used this opportunity to replace the very plain plastic buttons with hand-made ceramic buttons that are much nicer---little blue dragonflies on a Navy background that went better with the blazer, which, being plaid, will always be a somewhat informal blazer. I got the buttons from BeadFreaky for $18, which is a little weird for a $10 jacket. It took me about 90 minutes to replace the buttons, and about 5 hours to alter the sleeves---which could probably be cut down to 2 hours with more practice.